The use of complementary and alternative medicine (CAM) is widespread throughout the US and the world, although different ethnicities may vary in their use of CAM. Although CAM use is common to all socioeconomic and demographic groups, most of our knowledge is based on studies of non-Hispanic White adults, or very small studies of Hispanics. Preliminary studies indicate relatively common CAM use among older Mexican Americans with chronic medical conditions, but relatively few who rely solely on CAM. Among Mexican Americans, the popularity of herbal medicines may represent a strong link to traditional culture and belief. In this study, we will undertake the first comparative analysis of the use of CAM and related health services by older adults in Mexico and the USA. The data sets to be analyzed are: The Hispanic-Established Populations for the Epidemiologic Study for the Elderly (H-EPESE) and the INEGI (Institute Nacional de Estadistica, Geografia, e Informatica) National Mexican Health and Aging Study (NMHAS). We will focus on the 75+ year old Hispanic population, a group most commonly affected by chronic medical conditions such as pain-arthritis, depression, diabetes, heart disease and hypertension. We will systematically examine the relationship between self-reported functional status, social networks, health beliefs and similarities in usage patterns of CAM, pharmacists and health care services. Our Specific Aims are to: 1)document the prevalence, correlates and effects of CAM use over a 10 year period in a well-defined sample of Mexican American elderly 75+ years (Hispanic EPESE) in relation to the contribution of functional status, family and social networks, and health beliefs and preferences regarding use of standard health care services and CAM; and 2) compare the prevalence and correlates of CAM use for the Mexican Americans in the Hispanic EPESE cohort to CAM use among Mexicans of the same age and living in Mexico, using data from the NMHAS. Through this secondary analyses of data on CAM use in Hispanics in the US and Mexico, we seek to understand not only longitudinal CAM use in an elderly population, but also to compare, for the first time, similar variables across two data sets, and operationalize them in the same way. The unique characteristics of the available data sets will make possible secondary analyses such as a comparison of health behaviors between Mexicans born in the USA and those who emigrated from Mexico.